1. Technical Field
This invention relates to the field of optical communication systems and, more particularly, to an optoelectronic terminating module for an optical fiber cable.
2. Description of the Prior Art
In a module known from U.S. Pat. No. 3,950,075, a mounting for an optical lens consists essentially of a plastic ring, the deformability of which is utilized to push it self-clamping onto a spherical lens used as a focusing lens. This known module already has the advantage that, by means of the lens system, here formed by a single spherical lens, it is possible to obtain, at least for a time, a very good optical adaptation between the component and the light waveguide supplied to the module extraneously.
It turns out, however, that the known module is not capable of function for a sufficiently long enough period of time in many applications. Tests of this known module have shown that contaminations of the gas inside the module can occur which can adversely affect the qualities of the component over time. These contaminations were caused primarily by the declining tightness of the gap between ring and spherical lens and/or between ring and housing wall. While remedies such as cementing the spherical lens into the plastic ring--also into a ring of a different material--had the effect that the spherical lens and the ring were insertable into the module housing wall hermetically tight at first so that no contaminants impairing the module qualities could penetrate from the outside, it turned out that such insertions often did not remain hermetically tight as time progressed. The adhesive would frequently develop cracks, and even the plastic of the ring itself was not entirely gastight and moisturetight. Beyond this, there was a danger of smearing the lens systems with adhesive during manufacture or during an attempted maintenance procedure.
Thus it became an object of the present invention to improve the long-term behavior of the module, in particular, to increase substantially and with great certainty the length of time during which the component is fully capable of operation and, in particular, free of contamination.